Sibling cannibalism in the false widow spider is dependent on spiderling density and the reliable availability of fresh prey

Abstract Adult female spiders lay batches of eggs in silken egg sacs, and after hatching, the spiderlings live for transient periods their mother's web before dispersing. Sibling cannibalism is frequently observed among many species under conditions food deprivation. Here, we conducted assays small Petri dishes with different densities newly hatched (second instar) false widow spider, Steatoda grossa , using a split‐clutch design. Prey (freshly killed fruit flies) availability was manipulated both numerically temporally. Offspring from 10 females were separated as siblings into two, four, or eight per dish these provided either 0 flies (starvation control), two flies, four that replenished weekly every 3 weeks. A further control solitary deprived flies. The number surviving counted days until only one remained (or death spiderling). Our results show rate lower increasing spiderling density when fresh more frequently, whereas did not affect cannibalism. In S. juvenile occurs primarily extreme limitation, although synanthropic habitats where spider abundant, it may be an adaptive strategy owing to potential scarcity prey. Under certain conditions, by eliminating competitors providing nutrient‐rich food.